Does it refer to nuclear energy? Well, it is pretty harmful. It releases radioactivity and also waste which is extremely harmful for the biological system. Several incidents have been recorded where accidents have happened because of the nuclear energy. On the other counter, nuclear energy is a very good source for producing electricity to feed the world's growing demands and energy crisis.
For me, I think nuclear energy should be substituted by renewable sources of energy.
For instance ---
....we can produce electricity from the heat inside the earth(Geothermal energy);
....we can produce electricity from the waves created by the rivers and oceans(Hydropower);
....we can use the kinetic energy of the winds to produce electricity(Wind energy);
....using the sun's heat and light energy we can produce electricity(Solar energy);